HD 10180 - 6±1 planets

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Re: HD 10180 - 6±1 planets

Post by Lazarus on 29th September 2010, 2:57 am

As far as I can make out that is just numerology. They pull various quantities out of the air (e.g. taking sigma = 0.075, where do they get that from?). It's just Titius-Bode with fancier mathematics.
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Re: HD 10180 - 6±1 planets

Post by Sirius_Alpha on 5th April 2012, 8:37 pm

Lazarus wrote:More planets than any other known system... wait a second, eight is the number to beat, no?

Well...

Evidence for 9 planets in the HD 10180 system
http://arxiv.org/abs/1204.1254

We re-analyse the HARPS radial velocities of HD 10180 and calculate the probabilities of models with differing numbers of periodic signals in the data. We test the significance of the seven signals, corresponding to seven exoplanets orbiting the star, in the Bayesian framework and perform comparisons of models with up to nine periodicities. We use posterior samplings and Bayesian model probabilities in our analyses together with suitable prior probability densities and prior model probabilities to extract all the significant signals from the data and to receive reliable uncertainties for the orbital parameters of the six, possibly seven, known exoplanets in the system. According to our results, there is evidence for up to nine planets orbiting HD 10180, which would make this this star a record holder in having more planets in its orbits than there are in the Solar system. We revise the uncertainties of the previously reported six planets in the system, verify the existence of the seventh signal, and announce the detection of two additional statistically significant signals in the data. If of planetary origin, these two additional signals would correspond to planets with minimum masses of 5.1$^{+3.1}_{-3.2}$ and 1.9$^{+1.6}_{-1.8}$ M$_{\oplus}$ on orbits with 67.55$^{+0.68}_{-0.88}$ and 9.655$^{+0.022}_{-0.072}$ days periods (denoted using the 99% credibility intervals), respectively.

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Re: HD 10180 - 6±1 planets

Post by Daniel on 5th April 2012, 11:29 pm

So what is the Best solution the 6 planets or 9 planets? It's seems that both are 99% ok
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Re: HD 10180 - 6±1 planets

Post by tommi59 on 6th April 2012, 10:39 am

Periods close to 10 and 67 are significant very likely they are planets -nice Twisted Evil almost fell from chair
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Re: HD 10180 - 6±1 planets

Post by tommi59 on 6th April 2012, 5:24 pm

Maybe 10th planet in HZ ??Now time for new planets in 61 virginis
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Re: HD 10180 - 6±1 planets

Post by Sirius_Alpha on 19th August 2014, 8:44 pm

On the Inclination and Habitability of the HD 10180 System
http://arxiv.org/abs/1408.4150

There are numerous multi-planet systems that have now been detected via a variety of techniques. These systems exhibit a range of both planetary properties and orbital configurations. For those systems without detected planetary transits, a significant unknown factor is the orbital inclination. This produces an uncertainty in the mass of the planets and their related properties, such as atmospheric scale height. Here we investigate the HD~10180 system which was discovered using the radial velocity technique. We provide a new orbital solution for the system which allows for eccentric orbits for all planets. We show how the inclination of the system affects the mass/radius properties of the planets and how the detection of phase signatures may resolve the inclination ambiguity. We finally evaluate the Habitable Zone properties of the system and show that the g planet spends 100\% of an eccentric orbit within the Habitable Zone.

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Re: HD 10180 - 6±1 planets

Post by Shellface on 19th August 2014, 11:38 pm

I would make a comment on the interesting choice of title, but why do you imply 5 planets to be valid?

Anyway… to put my spin on this, the rotational inclination of the star is >~60°, and assuming system coplanarity that means M is no more than 1.15 times M sin i. Any inclination in that range has relatively little impact on the system's nature.

As for observing the system inclination, wouldn't, like… astrometry be better? I don't know the formulae, but I expect h's astrometric signal should be within the order of magnitude of detectability with modern levels of precision. Transits still haven't been invalidated yet, either, and the prior-adjusted transit probability for c is about 15%.

…Does anyone know the formulation for the HZ boundaries used here? I thought the method I was using was right, but the numbers don't agree. Though they don't seem to consider luminosity directly…?

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Re: HD 10180 - 6±1 planets

Post by Sirius_Alpha on 19th August 2014, 11:57 pm

At the time of the original announcement (and the creation of the thread) the b and h planets were described as "unconfrimed" or "uncertain."

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Re: HD 10180 - 6±1 planets

Post by Lazarus on 20th August 2014, 4:12 pm

The HZ calculations use Kopparapu et al. (2014).

Conservative = runaway greenhouse (1 Earth mass), maximum greenhouse
Optimistic = early Venus, early Mars

Personally I'm a bit disappointed they didn't address the non-detection of planet b in a bit more detail given that both previously-published solutions detected that orbital period.
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Re: HD 10180 - 6±1 planets

Post by Led_Zep on 6th January 2017, 12:49 am

SPITZER didn't found  transit in HD 10180 system :

https://arxiv.org/abs/1701.01303

The Spitzer search for the transits of HARPS low-mass planets - II. Null results for 19 planets
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Re: HD 10180 - 6±1 planets

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